Yes, I agree the behavior of the droid armies is also seriously suspect. First off, they act like eight year olds walking through the forest, noticing things but not taking any kind of military posture. But if they were real, they would communicate at the speed of light, some of them working as sensors, some laying down defensive fire, and others manuvering or attacking. If they couldn’t neutralize a threat, they would just pull back a little and nuke the whole area. If they knocked out a few of their own, so what. We can make more.
Still, my biggest objection is that the force is wide open full contact all out combat. But in the later movies, it seems the force is not the fearsome weapon it was before.
I also think the defensive fire from the Death Star in Episode IV would have been much more effective.